DescriptionThis is a small aeolidacean that rarely exceeds 5-6 mm in length. His body is thin, semitransparent, at times with a yellow or pink shade. Oral tentacles are relatively short compared to the rhinophores, which are very long, thin and smooth. The oral tentacles and rhinophores are semitransparent like the body, but with numerous thick white scores. These white scores are also present along the back. There are 4-5 groups of cerata on each side of the body. The cerata from each group come from a common stalk or base. The cerata are thin and long, with somewhat sharpened tips and the soft brown digestive gland visible by transparency; at the end of cerata there is a clearly visible cnidosac. At the base of each cerata there is usually a greenish spherical structure that Schmekel (1965) attributed to a glandular portion of the hepatic diverticulum located inside each cerata. Sometimes this green sphere, which this species is named for, is not visible, which could be related to feeding. The foot is narrow and has two short propodials palps at its front. The tail is long and narrow, it is semi-transparent and its margin is usually pigmented opaque white.

BiologyThis small aeolidacean lives among colonies of epibiont hydroids that grow on different species of algae and seagrass (Ulva, Cymodocea, Posidonia oceanica). Mavric et al. (2012) found it in the Adriatic Sea between scyphopolyps of Aurelia aurita. Schmekel (1965) indicates that it feeds hydrozoan polyps of the genus Obelia. The spawn is a coiled narrow ribbon with white eggs of about 45 microns in diameter.

Etymology

Piseinotecus means “I stepped on Teco.” Teco was a dog belonging to Ernst and Eveline Marcus. Apparently Prof. Diva Diniz Corrêa, friend of the family, unadvertedly stepped on the dog and while the Marcuses were looking for a new generic name she said in Portuguese: “Pisei”=I stteped, “no”=onto, “Tecus”=the dog’s name. Later on that name became also a family name: Piseinotecidae (ref:Curious Taxonomy and Marcus, Ev. 1987).

Sphaeriferus. From Latin “Sphaera”, ball, sphere, globe, orb + “fera”, to carry, to transport, probably in reference to the peculiar emerald green “balls” located at the base of the cerata.

DistributionThis little-known species has only been recorded so far in the islands of Nisida and Procida (type localities for this species) in the Gulf of Naples, in the Canary Islands (Ortea et al. 2003), Ghana (Edmunds, 1977 ), on the Adriatic coast of Slovenia (Mavric et al. 2012) and in Catalonia (Spain). There is a recent report in the Catalan coast, at Punta del Romaní (L’Escala, Costa Brava) (GROC, 2014), and there is also an ancient unpublished observation at Cala Canyelles (Ballesteros, pers.obs. 1981).